Wet air scrubbers (WAS) are used in a number of different markets some of which are: wastewater treatment for odor, meatpacking plants for odor, sulfur removal from power plant combustion and for gases evolved in the process of manufacturing electronics. These pieces of equipment are similar to cooling towers when looking at their basic design, however they are not involved in a cooling process. They are used primarily to absorb or as a medium for reaction with offending gases in a train of highly dispersed water droplets.

Most of these designs are countercurrent where the water is sprayed from the top of the unit and the air is pushed from the bottom of the unit. Wet air scrubbers suffer from many of the same problems as cooling towers such as scaling, corrosion and biological growth. However, air scrubbers have other problems such as pH of the gases and the ability to hold odorous substances. Many times, those problems are handled with the addition of an oxidant such as chlorine, chlorine dioxide and sometimes ozone. The use of bacteria for breaking down and assimilating offending compounds is also becoming more common.

pH, conductivity and ORP are common and may involve the oxidants mentioned previously and the use of sulfuric acid or caustic. There may also be nutrients fed to bacteria or scale and corrosion inhibitors added in addition to the other chemicals. Most systems will have additional equipment in the form of flowmeters, chemical pumps, level sensors and possibly chemical tanks. INT-9 controllers are chosen because they have integrated sensors, additional digital and analog inputs, data logging for troubleshooting, and remote communications.

Many of these air scrubbers sold into the manufacturing market are being shipped to Asia. These increases the value of the INT-9 controller because it can be accessed remotely from anywhere in the world for a very low cost when it is web-based. This is a major advantage over most other PLC and standalone controls. These systems can also be monitored 24/7 using Fluent by the system builder for a fee. The fee becomes an added revenue stream and the service will also help to sell parts and fulfill warranties.